Having started preschool just two weeks earlier, he returned home t with a sticker for helping to tidy up at nursery and practiced crossing his legs for class on Wednesday January 20 – but within 24 hours a rare bug that led to meningitis claimed his life.

Vicky and Mark Walter, who lost their son Henry, are pictured with their daughter Tilly. Picture by Bruce Rollinson.'''Read more: http://www.yorkshireeveningpost.co.uk/news/meningitis-warning-after-three-year-old-leeds-boy-dies-within-hours-of-falling-ill-1-7928668#ixzz49f5W1y1f

Four months on, Mark and Vicky, who also have an eight-year-old daughter named Tilly, are still coming to terms with the sudden loss of their son but have a clear message to other parents nationwide - “The main thing is you should always err on the side of caution. Don’t wait for a rash.”

After eating his supper, Henry went to bed at 7.30pm before complaining of a stomach ache. His mum Vicky, 36, gave him Calpol but an hour later, he vomited.

He had developed a temperature but had no visible rash, so once his dad Mark, 48, arrived home from work he nursed his son to sleep thinking the bug would pass.

“At 5am I found I couldn’t wake him, he was breathing funny, we rang the ambulance and a responder came within 90 seconds,” he said.

Henry was rushed to hospital where it emerged he had the rare bug Haemophilus Influenzae Type F, which had developed into meningitis – the life-threatening inflammation of the membranes that surround and protect the brain and spinal cord.

Mark continued: “Within about 20 minutes of us arriving at resus they told us he wasn’t going to make it – it was that quick.”

The couple were informed Henry had no brain stem activity and had to take the heartbreaking decision to turn his life support machine off.

“He was a lovely, bright three-year-old boy,” Mark said. “He loved dinosaurs, he could name them and he was bright. He was very advanced in his speech and he was just a fun-loving little boy.”

Friends and family have rallied round the Walters who live in Leeds, and have planned a series of events in honour of the three-year-old and in support of the Meningitis Now charity starting this week. Plans to plant a tree in Henry’s memory have also been mooted.

Mark also plans to do a sponsored bike ride in aid of Meningitis Now, which supports affected families and funds research, while friends are fundraising in memory of Henry by taking on the Edinburgh Marathon this weekend.

Mark said: “We’ve had a few donations from friends and people saying ‘I’m sorry it can’t be more’. It’s not about the money, it’s about keeping his memory alive and wanting something positive to come out of something that doesn’t seem to have any positives.”

The loss of their son has left the family intent on raising awareness of the signs of the extremely rare bacterial infection Haemophilus Influenzae Type F, which has no known vaccine.

Symptoms include fever, headache, nausea, cold hands and feet, drowsiness and sometimes but not always blotchy skin. The Type F strain is not covered by the much-debated MenB vaccine or the established Hib jab, which protects against Haemophilus Influenzae Type B.

There were 10 reported cases of haemophilus influenza-related meningitis in England in 2014, although those were most likely linked to the more common Type B.

Mark said: “Just because you’ve had the jab doesn’t mean you can’t catch another strain. For us we thought like everybody else – that something like this couldn’t happen to our family.

“The main thing is you should always err on the side of caution. Don’t wait for a rash.”